I am starting to experience a new issue with my inWin 904 case primarily around the tempered glass. It limits airflow. Basically, when I start to play a demanding game, the GPU temperatures may hit over 100c. Without the Tempered Glass panel, it runs much cooler. The cooler on my GPU vents air to the sides. In several cases there are holes here so the hot air can evacuate. With mine there is tempered glass acting as a shield. The solution is to pick the right GPU for your case. So I will need to wait a few months on that with my panel open.
There is also another heat issue if you are using liquid cooled CPU coolers. I have a Corsair Hydro CPU cooler which keeps my CPU cool, but not the passively cooled components around it. What a fan cooler allows is for air to pass through the fins of passive cooled components. Without a CPU fan there is no air flow over these components which may begin running hot.
What I plan to do is get a liquid cooled GPU and a fan cooled CPU.